.box{
    width: 500px;
    height: 250px;
    position: relative;
    
  }
  .box-img{
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
    transition: all 1.5s;
  }
  .box-img:nth-child(1){
    opacity: 1;
  }
  .box-left{
    position: absolute;
    width: 25px;
    height: 50px;
    background-color: #00000050;
    color: #ccc;
    top: 100px;
    border-radius: 0 5px 5px 0;
    text-align: center;
    line-height: 50px;
    font-size: 27px;
    
  }
  .box-left:hover{
    background-color: #00000050;
    color: #fff;
  }
  .box-right{
    position: absolute;
    width: 25px;
    height: 50px;
    background-color: #00000050;
    color: #8f8d8d;
    top: 100px;
    border-radius: 0 5px 5px 0;
    text-align: center;
    line-height: 50px;
    font-size: 27px;
    right: 0;
    
  }
  .box-right:hover{
    background-color: #00000050;
    color: #fff;
  }
  .box-zhiding>ul{
    padding: 0;
    margin: 0;
    list-style: none;
  }
  .box-zhiding li{
    width: 10px;
    height: 10px;
    border-radius: 100%;
    background-color: #ccc;
    float: left;
    margin-right: 7px;
  }
  .box-zhiding li:hover{
    background-color:#fff ;
  }
  .box-zhiding{
    position: absolute;
    bottom: 30px;
    right: 100px;
  }
 